Detailed Electromagnetic Analysis of Variable Flux Reluctance Machines: Unveiling Torque Production Harmonics Through Winding and Permeance Functions

This paper investigates the analytical modeling of variable flux reluctance machine (VFRM) using the harmonic spectrum of winding and magnetic permeance functions. Mutual inductance and back-electromotive force of 6/4 and 12/10 VFRM topologies are obtained using harmonic series expansion of the winding and permeance functions. The harmonic components of synchronous torque are derived by performing a comprehensive analysis of the sinusoidal series attributed to the winding and permeance functions. An investigation is conducted concerning the impact of rotor skewing on the back-EMF and synchronous electromagnetic torque output of a 12/10 VFRM. The validity of the proposed model is confirmed through results obtained from finite element analysis (FEA) and experimental measurements of back-electromotive force (back-EMF) and torque.